A new species of Rubiaceae, Mycetia fangii, is described and illustrated from Guangxi, South China. The new species morphologically resembles M. mukerjiana but differs in the calyx bearing one short gland on each sinus, the calyx lobes much shorter than the corolla, and shorter bracts and bracteoles. It is one of the species with cauliflorous inflorescences in Mycetia. Further examination of herbarium specimens shows that M. apoensis, M. yatesii, and M. lanceolata (Ridl.) Ridl. (non Miq.) are conspecific with M. cauliflora, the type species of the genus. Thus the three names are here reduced to synonymy of the type species. A key to the species of the genus with cauliflory is provided at the end of this paper.